Enclosed device with cover-mounting means



Jan. 23, 1962 s. s. DOBROSIELSKI ET AL 3,013,127

ENCLOSED DEVICE WITH COVER-MOUNTING MEANS Filed Oct. 50, 1958 kE13 i/ l Tn 19 19 9 l7- I I2 WITNESSES INVENTORS Q William L. Lang and gw Stephen s. Dobrosielski tates atent SghlbJZ? Patented .ian. 23, 1962 3,018,127 ENCLOSED DEVHCE WITH COVER-MGUNTING MEANS Stephen S. Dobrosielsloi and William L. Lang, Beaver, Pa., assignors to Westinghouse Electric Corporation, East Pittsburgh, Pa, a corporation of Pennsylvania Filed Uct. 30, 1958, Ser. No. 770,796 4 Claims. (Cl. 292--251) This invention relates, generally, to enclosed electrical devices and cover-mounting means therefor and, more particularly, to spring biased captive cover-mounting means.

An object of the invention is to provide a captive member suitable for retaining an open-able cover on an enclosure.

Another object of the invention is to provide a captive member which normally will not become separated from the cover, but can be easily replaced in the cover.

A further object of the invention is to provide a captive member which is biased to a retracted position in the the cover when released from the enclosure.

Other objects of the invention will be explained fully hereinafter or will be apparent to those skilled in the art.

In accordance with one embodiment of the invention, the cover for an enclosure has an outwardly extending flange around its edge with a plurality of spaced raised portions or bosses thereon having holes therein through which cover retaining bolts extend. In each hole there is an internally threaded portion substantially midway between the ends of the hole through which the threaded portion of the bolt is turned as the bolt is inserted into the cover. The shank of the bolt is reduced in diameter between its threaded portion and the head to slide freely through the threaded portion in the hole, or the threads are raised, as rolling them on the shank. A coil spring is disposed on the bolt between the threaded portion in the hole and the head of the bolt to retract the threaded portion of the bolt into the cover when the bolt is dis engaged from the enclosure.

For a better understanding of the nature and objects of the invention, reference may be had to the following detailed description, taken in conjunction with the accompanying drawing, in which:

FIGURE 1 is a view, in elevation, of an enclosure having a cover fastened thereon by means of a plurality of captive bolts embodying the principal features of the invention;

FIG. 2 is an enlarged view, in section, taken along the line IIII in FIG. 1 and showing one of the bolts tightened to hold the cover on the enclosure; and

FIG. 3 is a view, similar to FIG. 2, showing the bolt loosened and retracted into the cover by the biasing spring.

Referring to the drawing, and particularly to FIG. 1, the enclosure shown therein comprises a cabinet 14} and an openable cover 11 which may be hinged to the cabinet by means of hinge members 12. The enclosure may be of a type generally known as explosion proof and it may be cast from iron or aluminum. if desired, the hinges 12 may be omitted and the cover merely bolted onto the cabinet, as will be described more fully hereinafter.

The enclosure may be utilized to house electrical apparatus, such as a circuit breaker or an electric switch. A handle 13 is rotatably mounted on the cover 11. The handle is utilized to operate the circuit breaker or other apparatus inside the enclosure by means of an actuating mechanism which may be of the type fully described in Patent 2,550,125, issued April 24, 1951 to A. E. Schueler and H. T. Walton. A threaded plug 14 is provided in the end of the cabinet 10 which may be removed from the cabinet to permit electrical connections to be made to the apparatus inside the enclosure. The cabinet 10 is provided with mounting feet 15 for mounting the enclosure on a suitable supporting structure.

As shown in FIG. 1, the cabinet 10 is provided with an outwardly extending flange 16 and the cover 11 is provided with a similar flange 17. The cover is retained on the cabinet by means of a plurality of bolts 18, each one of which extends through a raised portion or boss 19 on the flange 17 on the cover 11.

As shown more clearly in FIGS. 2 and 3, each bolt 18 has a head 21 at one end and a threaded portion 22 at the other end. The threaded portion 22 is screwed into a threaded opening 23 in the flange 16 of the cabinet 11: to fasten the cover 11 on the cabinet 10. A gasket 26 may be provided in a groove 24 around the face of the cover to aid in sealing the joint between the cover and the cabinet. A washer 25 and a lock washer 26 may be provided between the head 21 and the top of the boss 19.

In order to make the bolt 18 captive with the cover 11, thereby preventing it from becoming lost when the cover is removed, a threaded portion 27 is provided be tween the ends of the hole in the cover through which the bolt 18 extends. The threaded portion 27 is of the same diameter and threads as the threaded portion 22 of the bolt and the threaded opening 23 in the cabinet. The hole for the bolt has an enlarged portion 28 at the upper side of the threaded portion 27 and another enlarged portion 29 at the lower side of the threaded portion 27. The diameter of the enlarged portion 29 is greater than the diameter of the threaded portion 22 of the bolt, thereby permitting the threaded portion 22 to move freely in the enlarged portion 2?. The diameter of the enlarged portion 28 is preferably greater than the diameter of the enlarged portion 29. The shank or the portion 31 of the bolt between the threaded portion 22 and the head 21 is reduced in diameter, thereby permitting this portion of the bolt to move freely through the threaded portion 27 in the hole.

As shown in FIG. 2, a coil spring 32 is disposed on the shank 31 of the bolt in the enlarged portion 28 between the threaded portion 27 in the hole and the head 21 of the bolt. When the bolt is screwed into the cabinet, as shown in FIG. 2, the spring 32 is compressed. When the bolt is unscrewed from the opening 23 in the cabinet, as shown in FIG. 3, the spring 32 raises the bolt to the position shown in FIG. 3 in which the threaded portion 22 of the bolt engages the bottom of the threaded portion 27 in the cover. The length of the enlarged or counterbored hole 28 is greater than the length of the spring 32 when it is compressed. This makes it possible for the underside of the head 21 of the screw, or the under side of the washers 26 and 25, if used, to engage the upper surface of the cover surface and apply the holding force directly thereto without the force being transmitted through the spring. Thus, the spring is entirely enclosed within the recess 28 below the outer surface of the cover 11. It will be noted that the length of the enlarged portion 29 of the hole for the bolt is equal to or greater than the length of the threaded portion 22 on the bolt, thereby permitting the lower end of the bolt to be flush with or slightly above the lower face of the cover. Thus, the depth of the material of the cover around the mounting holes is great enough to fully enclose the threaded portion 22 of the bolt, the threaded portion 27 of the hole, and the spring 32 when compressed.

In this manner, all of the bolts in the cover are prevented from becoming separated from the cover and they are all retained in a position in which they will not interfere with the replacement of the cover on the cabinet. Thus, the threads on the bolts are prevented from becoming damaged while the cover is removed and when the cover is being replaced on the cabinet. Each bolt can be removed from the cover for replacement by simply turn-- ing the threaded portion 22 on the bolt through thethreaded portion 27 in the hole in the cover.

When the cover 11 is fastened on the cabinet, the springs 32 are contained within the openings 28 inthecover. Thus, the only portion of each bolt which is exposed is the head 21. As previously explained, the threaded portion 22 of each bolt is contained within the opening 29 when the bolts are loosened to permit the cover to be removed from the cabinet. In this manner, the possibility of the bolts becoming lost or damaged is. precluded.

From the foregoing description, it is apparent that theinvention provides for making captive the bolts which are utilized for retaining a removable cover on a cabinet. The bolts are retracted to a position within the cover where the threads on the bolts are protected and the bolts will not interfere with the replacement of the cover on the cabinet. The bolts may be completely removed from the cover if it is so desired.

Since numerous changes may be made in the above described construction and different embodiments of the invention may be made without departing from the spirit and scope thereof, it is intended that all the matter contained in the foregoing description as shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

We claim as our invention: 1. In combination, an explosion-proof enclosure comprising a cabinet and an openable cover, said cabinet having an open side with a peripheral flange extedingtherearound, a plurality of spaced threaded openings through said peripheral flange, said cover having a registering peportion being of a larger diameter than the threaded portion, a fastening member rotatably disposed in each hole,

each fastening member having a head portion at one end and a threaded portion at the other end of the same diameter and threads as the' corresponding opening in the cabinet, a portion of the fastening member between its head portion and its threaded poriton being ofa smaller diameter than the threaded portion in the hole, resilient means disposed on the small diameter portion of said rotatable fastening member, said resilient means being disposed in one of the larger diameter portions of the hole between the head portion of the rotatable fastening member and the threaded portion of theho-le to bias the rotatable fastening member away from the cabinet, and

a greater diameter than the internal diameter of said one larger-diameter portion of the hole, whereby said resilient.

means will not be compacted and mounting pressure will be applied directly to said boss portions of the openable cover.

2. The combination according to claim 1, wherein said head portion of the fastening member includes a loose washer and a lock washer.

3. In combination, an explosion-proof enclosure comprising a cabinet and an openable cover, said cabinet having an open side with a peripheral flange extending therearound, a plurality of spaced threaded openings through said peripheral flange, said cover having a registering peripheral flange with a plurality of spaced boss portions, each boss portion of the peripheral flange of the cover having a hole extending therethrough registering with a corresponding opening in the cabinet, a threaded portion in each one of said holes in the boss portions of the cover, said threaded portion being integral with the cover and spaced from the ends of the hole in the cover, said threaded portion being of the same diameter and threads as the corresponding threaded opening in the cabinet, the portions of the hole on opposite sides of the threaded portion being of a larger diameter than the threaded portion, a mounting bolt rotatably disposed in each hole, each mounting bolt having a head at one end and a threaded portion at the other end of the same diameter and threads as the corresponding opening in the cabinet, said mounting bolt being of a reduced diameter between its head and its threaded portion to be freely movable in the threaded portion of the hole, the threaded portion of the mounting bolt being freely movable in one of the enlarged portions of the hole, the length of said one enlarged portion being no less than the length of the threaded portion of the mounting bolt to shield said threaded portion of the mounting bolt, a coiled compression spring disposed on the reduced diameter portion of the mounting bolt, said coiled compression spring being disposed in the other enlarged portion of the hole between the head of the mounting bolt and the threaded portion of the mounting hole to bias. the bolt away from the cabinet, and the head of the. mounting bolt being of larger diameter than the internal diameter of said other enlarged portion of the hole to prevent compacting said coiled compression spring and to apply mounting pressure directly to the external side of the boss portion of the cover.

4. The combination according to claim 3, wherein a loose washer and a lock washer is employed under said head of the mounting bolt.

References Cited in the file of this patent UNITED STATES PATENTS 748,078 Kaisling Dec. 29, 1903 1,927,780 Anderson Sept. 19, 1933 2,564,101 Dzus Aug. 14, 1951 

